Blemishes are flaws that are found on the surface of the diamond. These are not usually as damaging to a diamond’s clarity grade as inclusions, as many blemishes can be polished away prior to the grading. This type of flaw can be formed as either a natural part of the diamond’s growth or as a result of the cutting and polishing process. Knowing the names of different blemishes, and being familiar with their descriptions and definitions will afford you a greater ability to differentiate between diamonds with blemishes that are potentially damaging to the light transmission qualities of the diamond, and diamonds that have innocuous blemishes.
- Polishing Lines: Polishing lines arise during the cutting process of the diamond. In form they appear as grooves or scratches, usually running in parallel lines on the facet or facets of the diamond surface. These lines can be negligible in regards to the overall clarity and grade of the diamond if they are quite small and if found on the pavilion.
- Naturals: Naturals are flaws that are not always considered flaws. They are small portions of the original rough diamond’s surface that are left unfinished or unpolished by the cutter. While this might seem odd, it is normally done in order to save diamond weight during the cutting process, and also serves as indication of the skill of the cutter. These are normally found on the diamond’s girdle and do not detract from the diamond’s clarity grade if they do not overly extend or expand the diamond’s girdle.
- Trigons: Trigons are raised triangular shapes that are found on the surface of a diamond. The triangular shape is the result of the octahedral crystalline structure that makes up a diamond, as the face of the octahedral form is a triangle. These can be formed as a natural growth of the crystalline structure, but can also be formed during the cutting and polishing process.
- Pits: Pits can be some of the more problematic of blemishes. Pits are tiny holes, often appearing as white dots, appearing on the surface of the diamond. The location of the pits is critical to its impact on the grade of the diamond. Should the pits appear on the table of the diamond, they can be detrimental to the light qualities, and so precipitously lower the diamond’s grade. Smaller pits can be polished away, but larger pits occurring on the diamond’s table may require re-cutting the table, causing the diamond to lose some of its weight.
- Scratches: Scratches are simply that, scratches on the surface of the diamond. These are not unusual and can appear as thin, white lines, shallow in depth and narrow in width. Scratches can detract from a diamond’s grade, but scratches can usually be polished away. It is important to be aware, however, that while a diamond can be re-polished to its original shine, it must be removed from its setting in order to allow for the re-polishing process.
- Nicks: Nicks are small areas of the diamond where an impact has caused a tiny portion of the diamond to break away. These are most often found on the diamond’s girdle, as the girdle is the most extended and at-risk part of the diamond. Nicks can be polished out through the polishing down of a new facet. It is important to note that while this can solve the problem of a small nick, too many additional facets will negatively affect the appearance and light qualities of a diamond.
Nevertheless, it’s nice to avoid major blemishes on the diamond of your engagement ring.